1. Field of the Invention
The present invention relates to a cylindrical shock absorber with a cover used for such as a rear wheel suspension of a two-wheeled vehicle.
2. Description of the Prior Art
An example of such a cylindrical shock absorber with a cover is shown in FIG. 4. The drawing is a complete sectional view in an axis direction of the cylindrical shock absorber with a cover, which comprises an oil pressure damper a, piston rod b, a cushion spring c, spring seat d, an adjuster e, and is provided with a cover f covering a part of the cushion spring c integrally with the spring seat d.
The adjuster e is a member for adjusting a pre-load of the cushion spring c and is capable to freely move for adjusting in an axis direction integrally with the spring seat d by rotating on an outer face of the oil pressure damper a. This adjustment is arranged, as shown in FIG. 5, to be performed in a step-like by means of making a cam portion g formed on an end of the adjuster e to engage with an adjusting stay h secured on the oil damper a. The cover f is a part greatly requested to adopt from a point of view of the design especially in such a vehicle as an American version motor-cycle.
In the cylindrical shock absorber with a cover such as above mentioned, the adjuster e is pushed toward the adjusting stay h which is provided previously in a pair at 180 degree interval on a peripheral direction of the oil pressure damper by means of a reaction force of the cushion spring c, and supported by two contacting points with the adjusting stay h. Because there is some gap for sliding between the adjuster e and the oil pressure damper a, when the cushion spring c resonates through the vibration generated by such as an engine, the adjuster also tends to resonate to amplify the vibration as shown in FIG. 5.
Because, when such a phenomenon occurs, the spring seat d integrated with the adjuster e amplifies the vibration also, the vibration of the cover f integrated therewith is enlarged and the cover c contacts with the cushion spring c to easily generate an unusual noise.
Accordingly, for avoiding the generation of such an unusual noise, it is required to enlarge a diameter of the cover f to keep a sufficient distance to the cushion spring c. However, this causes inevitably the whole cylindrical shock absorber with a cover to become large, so cannot satisfy with a strong demand in recent years for making it compact. It is an object of the present invention to resolve such a problem.